{	Problem: http://codeforces.ru/problemset/problem/34/A
	Verdict: Accepted

}
var n,i,x,y:longint; a:array[1..1001] of longint;
begin
readln(n);
for i:=1 to n do read(a[i]);
x:=1;
y:=2;
for i:=3 to n do begin
  if abs(a[i]-a[i-1])<abs(a[x]-a[y]) then begin
    x:=i-1;
    y:=i;
  end;
end;
if abs(a[n]-a[1])<abs(a[x]-a[y]) then begin
  x:=1;
  y:=n;
end;
writeln(x,' ',y);
end.